By "box" speakers, I take it you are talking about bookshelves, right? There are two things that I think deserve keeping in mind if you are worried about bookshelf speakers' sound quality.

First, the basics of speaker design are well established and have been for some time now. Advancements in construction materials offer some advantages today - you can find some pretty exotic alloys and interestingly-formulated composites in driver cones, for example - but the basics of producing sound from a mechanical device are such that you won't see the sort of revolutions that video display technology or data storage have enjoyed. It's all about refinement, quality, and filling the market need. This can be done in a tower or a bookshelf equally well, with the only difference being the lowest octave (although there are certainly some designs like electrostatic where a bookshelf isn't really an option). That seques nicely to...

Second, even tower speakers are rarely true "full range" speakers. They are likely to roll off somewhere between 30Hz and 50Hz (plus or minus about 10Hz), giving them an advantage over bookshelves that might start to roll off anywhere from 50Hz to 80Hz or above. Even with that advantage, though, they typically still can't reach all the way down to where human hearing stops. For a very long time, that limitation was not enough to bother most music listeners, but movies and certain kinds of music routinely venture deeper than that - at which point even towers fall short. That's why you see subwoofers as an integral part of most home theaters, and once you add a good subwoofer (or more than one, depending on the person and the space) you can start crossing over to it high enough that the tower's better "reach" ceases to provide an advantage. Once you hand off everything below 80Hz to a subwoofer, a bookshelf speaker should be able to match a similar tower speaker if everything else is equal.

Take your Orb Mod 2 system as a somewhat extreme example of a modern sat/sub system. The satellites are listed as having a frequency response of 80Hz to 20,000Hz, with an "optimal" frequency response of 120Hz to 18,000Hz (which I take to mean the first set of numbers are at -6dB or so and the second set are at -3dB). This is actually fairly respectable for a one-way speaker design. Compare that performance to what the Outlaw Bookshelf can do without help from a sub: 54Hz to 22,000Hz +/-3dB (which plenty of comparable ported bookshelves can match, while sealed designs like the LCR typically won't go quite as deep). You can start to see that bookshelves can do a lot on their own. Also, I did some reading up on the DC-10, and while frequency response data eluded me I did find one write-up that indicated that it was often used with a subwoofer (Dahlquist apparently even made one specifically for it, called the DC-1W), which takes us back to my second point - even towers are rarely "full range" speakers by themselves.